A call completion refers to a successful completion of a call, and a call completion rate refers to a probability of successful calls, which is equal to a rate of the desired number of successful calls to the number of total testing calls.
In the existing mobile communication network, when a mobile terminal selects a cell A but the cell A is in a network congestion state, the mobile terminal will perform the first switch to switch from the cell A to a cell B. If the cell B is also in the network congestion state, the mobile terminal will perform the second switch. During the second switch, the mobile terminal may select the cell A again. Since the time elapsed between two switches is short, the cell A may be still in the network congestion state, resulting in that the mobile terminal cannot access the cell A, thus resulting in a low call completion rate of the mobile terminal.